Different ranges of celestial bodies

1. Star   a large light producing object (through nuclear fusion) whose gravity is large enough to pull other objects near it.   

Life of a star = nebula  nuclear fusion core collapse2. Planet  an object, which orbits a star3. Satellite  an object which orbits a planet ex.  

moons, artificial satellitesGalaxies

A galaxy is a massive group of stars, gas and dust all held together by gravity. Galaxies contain upwards to 100 billion stars.  

You Earth  Solar System  Milky Way Galaxy Earth is a planet in our solar system.  Our solar system is one of many in the Milky Way Galaxy.  The Milky Way Galaxy is one of many in the Universe.

The Milky Way is 75 000 light years in diameter.  It is a spiral galaxy because of its shape.  The Sun is located near the outer part of the spiral. The band that we can see occupies about 400 billion stars.

The main types of galaxies are:

Spiral - galaxy with tightly wound spiral arms

Elliptical - slightly elliptical to nearly circular

Barred Spiral - spiral with a bright bar of gas through the center

Peculiar - fits none of the descriptions

Irregular - small, patchy, irregularly shaped galaxy

The closest galaxy to us is called Andromeda (2.5 million light years away). It is visible with the naked eye! It was discovered by Edwin Hubble in 1925.

The "Hubble Deep Field" image was taken by the Hubble Space Telescope December 18 - 28, 1995. It was taken of a region near the handle of the Big Dipper, and covers a patch of

sky about only 0.05 degrees across (equivalent to the width of a dime viewed 75 feet away). This region was chosen because there are very few stars there. So nearly every object in the image is a galaxy.

Using the “Hubble Deep Space Image” identify the types of the ten galaxies labeled on the Deep Survey Image.